Variable-pitch propeller.



S. D. MOTT.

VARIABLE PITCH PBOPELLER. APPLICATIQN FILED Nov.21`.1915.

Patented Sept. 24, 1918.

2 SHEETS-SHEET l.

WITNESS/:"8

S. D. MOTT.

VARIABLE FITCH PROPIELLER.

APPLICATION FILED NOV-'27'. I9I5- Patented Sept. 24, 1918.

2 SHEETS-SHEET 2.

SAMUEL D. HOTT, 02|."

Specification of Letters Patent.

a UNITED STATES PATENT OFFICE. Y

Passaic, Nnw zrnnsnnassreNon. or ONE-Hams` 'ro B. SULLIVAN, orALLENDALE, NEW JERSEY.

Patented sept. 24, 191s".

Application led November 27, 1915. Serial No. 63,710.

struction, and more particularly air propel- 1ers such as used forpropelling air-craft, and the partlcular object is to produce a variablepitchpropeller, but in practical manner. -Moe particularly. the objectis to eiiect the desired result in a simple, strong and reliableconstruction capable of meeting the exacting requirements of aeroplanepropellers and the like, roperly balanced as to adjustmentof pitc andchangeable or variable in a degree suiiicient for all practicalpurposes, and at the same time light and reliable, and operable in. aconvenient manner when in operation, to meet the varying conditions ofstarting and changed air conditions. To accomplish this result with alight construction of maximum strength, .will appear as one of the mostimportant features of my invention. Particular embodiments of myinvention are shown in the accompanying drawings, in which:

.Figure I is a part sectional view of the axis of the propeller shaft,Apartdiagrammatic. p

Fig. II is the main shaft'removed from the structure.

Fig. III is an end view of a blade showingl ig. VI is a side view of thepitch adjusting mechanism in the duplex apparatus, at

'section VI-VI The main drive shaft -1 has mounted on it a hub 2 of awire spoke wheel 3, havin a.

rim 4;.while the secondhub 5 with wireA spoke wheel 6, and rim 7 arelikewise mounted on the drive shaft 1. Bletween the hubs A l is abladepivot flange 8, to which blades 9-9 are attached with any suitablemeans such as the head 10.

The propeller blades are strengthened part way out from the center witha strap 11, With a hinged joint 12 firmly secured there to or integraltherewith, which is secured to the other hinged member 13 attached bysuitable collar or otherwise, to the wheel rims 4 and 7.

and. Within this sleeve is a rod 15. The

sleeve 14 has radial lugs 16, while the rod15 has at its extremity theenlargement 17 and integral. lugs 18.

The lugs 18 project throughy the helical slot 19 in shaft 1, and thelugs 16 project through the helical slot' 20, and in each c'ase the lugspass through openings in the hubs `within, the drive Shaft 1 is a Sleeve14,

2 and 5, respectively, the sides of these lugs 16 and 18 being slightlyinclined so'as to iit snugly into theV slots 19 and 20, and slidereadily in these slots.

Sleeve 14 and rodV 15, are secured at the A operable end to lugs 21-22.having threaded collars tllfroughwhich shifting screw 23 passes, whichscrew is supported in a rigid bearing 24, against axial movement, andhas an operating hand wheel 25.

Byfthe turning of the hand wheel 25, as

shwn in the drawing, the lugs 21-22- are.

moved apart by means of the lthreaded rod 23,'and the attached sleeve 14and rod 15 are the movement of the hand wheel 25 would gradually movethe lugs so as t0 jpull'the supporting wheel hubs 2 and 5, toward eachother, andas they move, the lugs 16 and 18 accordingly moved axiallywith respect to each other, which in turnproduces a movement of the lugs16-18. Considering Fig. I,

19420, which have beenv given 'a predeterl mined helical pitch. v Thismovement of the hubs 2 and 5, axially along the drive shaft 1, soproportioned with respect to the slots 19-20, that a relativecircumferential movement is given 4to the wheels 3.'and 6, in proportiontothe movement of the hubs on the shaft. By this slight circumferential"I relative motionthe necessary movement is `tion of the joints,oircumferentially, on the wheel rims 4 and 7, will thereby be changed toan Xtentn represented by the distance C and and this distance representsthe-required relative circumferential movement,

. and thereby slight rotary adjustment of the wheels 3 and 6 withrelation to the shaft to which they are splined orkeyed by the lugs 16and 18.

It will thus be seen that the construction is one capable of adjustmentby means of the turning of the hand wheel 25, by the operator of, forinstance, an aeroplane, while the propeller is in operation, and bysuitable proportioning of the hand wheel and the threaded or otherparts, sufiicient power may be readily available to accurately and sensitively adjust the pitch of the propeller without cramping of the movableparts, and without losing in any way the predetermined strength andsupport for the propeller, in allIpositions of adjustment.

. articular attention is directed to the use of the wire spoke wheels 3and 6, which are a most important element of the construction. Wheels soconstructed are known to give the strongest and lightest constructionfor articles of this character,-the tangential spoke with steel of hightensile strength combined with cold-drawn steel tubing of like hightensile strength, affords a structure which I have selected aspecnl-...f

iarly adapted to my invention.

By the arrangement described, the adjusting of the propeller pitch iseffected by movement of points on the propeller some distance out fromthe center, and the relative size of 'v'heels 3 and 6 compared with thelength of propeller blade, may even be such as to Support the sides ofthe blade at a point half wa resistance of the propeller blade. In anyevent having the support carried out a far eater extent than theordinary hub, afords a' support for the propeller which for givenstrength is effected with lightness far beyond what has heretbfore beenthe practice.

The movement or driving of the propeller may be effected in any mannerby the turning of shaft 1, by the gearing or chains, or direct couplingto motor,-any desired manner, being so optional that the driving owerhas been indicated on the drawing, ig. I,

out or even approximating the center Lavar-ta symbolically by theword-Moten which will be understood to mean any desired or suitabledriving means.

The light skeleton Wheels or tension spoke Wheels, may have their spokesmade of Wire having a ribbon section or fish-shaped secr tion, tominimizev the wind resistance in their rotation, and such flattenedspokes may in themselves be placed helically, thereby acting as smallblades to assist in propulsion, so that in a sense the whole hubstructure far from being a sourceof resistance, effects the desiredresult as to strength with an added advantage in efficiency of theentire propeller. v

In Fig. IV is shown, in part broken away, propeller shafts 26-27 drivinga pair of propellers, the shafts being` supported in bearings 28connected by transverse members 29. Any suitable propelling means may beapplied, as at 30, to drive the shafts 26-27 and the propellers.

The coperatlng adjusting rods 15 and sleeves 14 are brought into aposition so that the adjusting screw 23 may be operated by a bevel gear3l, which in turn is operated by bevel p1nions32, on a common shaft 33which is actuated b a hand wheel 34.

In this manner t e hand wheel 34 may be rotated, and through the gearsand adjusting screw will relatively move the pairs of adjusting sleevesand rod 1415, simultaneously so as to produce a simultaneous variationinthe pitch of the two propellers operating as a pair.

In similar manner a larger number of propeller-s coperating in onemachine may be adjusted simultaneously or in predetermined ratio. It iswell known that ropeller blades are designed with a @sur ace accuratelyprescribed for given conditions of operation, and that a single bladesurface' may not be equally efHcient when used or set at differentdegrees of pitch.

The variation of pitch however, is a desirable feature in certainconditions of operation, and the advantages gained are such as to makedesirable means of pitch adjustment practical from the standpoint ofstrength and structure and adjustment,- which will all be realized inthe practice of my invention.

Details of construction have been indicated in the particular embodimentherewith shown, in some respects symbolic or diagrammatic, whereas inpractice details are modified to permit the roper' assembling oradjusting of Parts, andp as to these details of construction, manyvariations may be made in dimension or arrangement.'

Furthermore, the structure in general may be modified in many ways fromthe exact embodiments which I have herein yshown and specificallydescribed, but what I claim and desire to secure by Letters Patent is:

termedate the hub and the radially outward end of the propeller, forythe purpose described.4

- 2. A variable pitch propellerl comprising -a drive shaft, twosupporting wheels on said drive shaft having axial movement thereon,means for slight rotary adjustment of said wheels, and 'means withinsaid drive shaft `for effecting said' axial and rotary adjust'- ment, anoperating mechamsm accessib e to the operator to adjust said hubs Whilesaid propeller is in motion, circular frames secured to and movable withsaid hubs, a plu- .rality of blades ha operation, to vary their p1 theirbutt ends pivotally xed adjacent t e shaft, and extending radially fromsaid shaft and having articulated' connections from said circular framesat points intermediate their huh connection and 'radial extremity.

3. Variable pitch propellers for air-craft, comprising a lurahty ofblades having a permanent ra 'al position with respect to the drivingshaft, and havingmeans for slight rotary adjustment of the bladesupporting-hub, with reference to the driving shaft` and means wherebyan operator may adjust a plurality of said ropellers while in *lichuniformly.

4. An air propellercomprising a plurality of blades, a dri've shaft,pivotal means of sup ort of eachblade adjacent the drive sha drivinghubs on said drive shaft on yopposite sides of the blade support, awheel on each hub and articulated means of sup- November, 1915.

port for each blade at the periphery of each wheel, means for va -thedistance between said wheels where ya variation of pitch of thepropeller'blades is effected, an operating means whereby said variationmay be1 1effected during the driving of the prope er.- l 5. An aeroplanepropeller, comprising a plurality of blades extending radially outwardfrom a drivin shaft, a hub connection for the inner end o each bladeadjacent the shaftz two relativel movable hubs on opgansite sides ofsaid b ade connections, circ r frames carried by said hubs and havingarticulated connections near their periphery for engagement with theblades intermediate their hubs and ends, means for mo said frame hubswhereby a uniform change 'fin the pitch of the propeller blades issimultaneously effected. v

6. An aeroplane propellercomprising a drive shaft, a plurahty of bladesextending from adjacentthe drive shaft radially outward, rsubstantiallyat right angles to the shaft, and havin a means of support adjacent theshaft, oo ars surroundin the shaft on the opposite sides ofthe bla e suports and carrying circular ramesrespective y, of "a radius less than theradius of the propel- 1ers, and attached to the propellers intermediatetheir hub and tip, relatlvely nearer the hub, whereby the most effectivereaction area of said blades is clear of any adjacent frame members.

In testimony whereof, I have signed my name to this specification, inthe presence of two subscribing witnesses, this 26th day of SAMUEL n.Morr. Witnesses:

HERMANN F. 'Ci-nvm, H. Muormonn.

l'Il

